1. Japanese are selling foreign investments and bringing money home so they need sell foreign currencies and buy Yun

2. Unwinding Carry Trade: in normal time, hedge funds borrow Yuan (because interest is low in japan), and invest in high yield currency (like australia dollar as austrlia has higher interest rate) to make the difference between two interest rates. But in volatile times, this kinda trade will be very risky, so this trade is taking off, and traders need sell foreign currency, buy Yuan and return Yuan to the lenders.

So when a lot of people all of sudden are selling foreign currencies and buy Yuan, Yuan will be strong